It is desirable for an exterior switch, e.g., an exterior vehicle switch, to withstand exposure to extreme weather conditions, abuse from a car wash, off-road activity, etc. Known switches may fail due to moisture ingress into the dry contact area of the switch. In one known configuration, a seal is established by a separate elastomeric membrane that is captured between two rigid components that combine to form a housing for the switch assembly. Screws are used to draw one rigid component toward the other, and fix the two rigid components such that they capture the elastomeric membrane. Features acting to impinge and clamp the elastomeric membrane may be added to the rigid components. The intent is to provide a watertight seal around the entire perimeter of the membrane. This approach to sealing may however be unsatisfactory, since the membrane can shift when coupled to the housing or during the assembly of the screws, thereby compromising the integrity of the seal.